Abstract: High precision measurement of torsional vibration is important for the torsional vibration analysis of shaft systems. Faked signals caused by the eccentricity of tooth discs can influence the measurement precision by entering into measurement signals. On the basis of an analysis for the faked signals, a quantified calculation and signal processing is provided to solve this measurement error caused by false signals. Using this method an analysis has been done for the result of torsional vibration test of one type of vehicle, and a signal compound has been obtained to correct the test result.